Abstract: The extract of digitalis leaves was chromatographed on a kieselguhr plate with formamide as the stationary phase, and chloroform-acetone-ethylacetate-ethylalcohol-formamide(8:2:0.5:0.5:satd.), or chloroform-butanol-formamide(9:l:satd.), or chloroform-ethylacetate-benzene-formamide(1:3:2:satd.)as the mobile phase (for the separation of primary glycosides of D. lanata, primary glycosides of D.purpurea,or secondary glycosides respectively). After development, the plate was heated at 100℃ to remove formamide, then placed in a glass jar containing iodine to reveal the spots, which were then drawn into microtubes by suction and eluted with a glacial acetic acid solution of xanthydrol, hydrochloric acid was then added, the solution was heated for 3 mins in a boiling waterbath and determined colorimetrically at 532mμ.The recovery of six pure digitalis glycosides was determined. Digitoxin, digoxin, lanatoside A, B and C could be recovered quantitatively,the average recovery was in the range of 94.9—97.6%, with a standard deviation of 0.6--2.3%. Gitoxin, because of tailing, gave only 87.7% recovery. The method has been applied to the assay of samples of D. lanata Ehrh.and D.purpurea L. The results were in agreement with those by paper chromatographic method. However, thin layer chromatographic method is more accurate and less timeconsuming, it is also easier to be performed.